This invention relates to a cutting insert pocket in a cutting insert holder that provides precise location of a cutting insert retained therein.
In the prior art a cutting insert pocket in a cutting insert holder generally comprises two angularly disposed sidewalls and a base transverse thereto. Normally, one of the sidewalls has one insert location surface and the other sidewall has two coplanar insert location surfaces. The three insert location surfaces define the position of a cutting insert retained in the cutting insert pocket.
A known disadvantage of this mode of insert retention is the lack of repeatability of location of the cutting insert, and therefore of the cutting insert""s operative cutting edge. That is, when indexing or replacing a cutting insert there is no certainty that the new operative cutting edge will be located in the same position, with respect to the cutting insert holder, as the previous operative cutting edge. A further disadvantage is the possible moving of the cutting edge to a new location due to a change in direction of the cutting forces acting on the cutting insert.
It is an object of the present invention to provide a cutting insert pocket that substantially overcomes the above mentioned disadvantages.
It is also an object of the present invention to provide a method for assembling a cutting tool assembly comprising a cutting insert and a cutting insert holder having a cutting insert pocket in accordance with the present invention.
In accordance with the present invention there is provided a cutting insert pocket in a cutting insert holder comprising:
two insert support sidewalls and a base transverse thereto, a first of the two insert support sidewalls being fixed relative to the base and having two coplanar spaced apart insert location surfaces, a second of the two insert support sidewalls being rotatable about an axis transverse to the base and having two coplanar spaced apart insert location surfaces, the two insert support sidewalls being angularly disposed to one another, the second insert support sidewall being the inner surface of a slidably rotatable member, the slidably rotatable member having an outer surface opposite an inner surface.
In accordance with the present invention, the outer surface of the slidably rotatable member has an arcuate portion and the cutting insert holder has a fixed inner wall adjacent the outer surface of the slidably rotatable member, the fixed inner wall having at least two spaced apart abutment surfaces, the arcuate portion of the outer surface of the slidably rotatable member being in abutment with the at least two spaced apart abutment surfaces enabling slidable rotational movement of the slidably rotatable member relative to the fixed inner wall of the cutting insert holder.
In accordance with one embodiment of the present invention, the outer surface of the slidably rotatable member has an arcuate portion with a first radius of curvature and the cutting insert holder has a fixed inner wall adjacent the outer surface of the slidably rotatable member, the fixed inner wall having an arcuate portion with a second radius of curvature, the arcuate portion of the outer surface of the slidably rotatable member being in abutment with the arcuate portion of the fixed inner wall enabling slidably rotational movement of the slidably rotatable member relative to the fixed inner wall of the cutting insert pocket.
In accordance with a preferred embodiment, the first radius of curvature is larger than the second radius of curvature.
Preferably, the arcuate portion of the outer surface of the slidably rotatable member is convex and the arcuate portion of the fixed inner wall is concave.
If desired, the arcuate portion of the outer surface of the slidably rotatable member is concave and the arcuate portion of the fixed inner wall is convex.
In accordance with the present invention, the slidably rotatable member is provided with a through bore and the base of the cutting insert pocket is provided with a bore, the slidably rotatable member being attached to the base of the cutting insert pocket by means of a pin which passes through the through bore and which projects from the slidably rotatable member into the bore.
In accordance with a preferred embodiment of the present invention, the bore in the base of the cutting insert pocket has a first diameter and the through bore in the slidably rotatable member has a second diameter, the first diameter being greater than the second diameter.
In accordance with the present invention there is also provided a cutting tool assembly comprising a cutting insert holder having a cutting insert pocket and a cutting insert retained therein, the cutting insert having at least two angularly disposed insert peripheral side surfaces, the cutting insert pocket comprising:
a slidably rotatable member having an inner surface and an opposite outer surface;
two insert support sidewalls and a base transverse thereto, a first of the two insert support sidewalls being fixed relative to the base and having two coplanar spaced apart insert location surfaces, a second of the two insert support sidewalls being slidably rotatable relative to a fixed inner wall of the cutting insert pocket and having two coplanar spaced apart insert location surfaces, the fixed inner wall being adjacent the outer surface of the slidably rotatable member, the two insert support sidewalls being angularly disposed to one another, the second insert support sidewall being the inner surface of the slidably rotatable member;
wherein the cutting insert is retained in the cutting insert pocket with the two coplanar spaced apart insert location surfaces of the first insert support sidewall abutting one insert peripheral side surface and the two coplanar spaced apart insert location surfaces of the second insert support sidewall abutting the other insert peripheral side surface, the slidably rotatable member being fixed in position between the cutting insert and the fixed inner wall adjacent the outer surface of the slidably rotatable member.
The is also provided in accordance with the present invention, a method for assembling a cutting tool assembly comprising a cutting insert holder and a cutting insert, comprising the steps of:
(i) providing a cutting insert holder having a cutting insert pocket, the cutting insert pocket comprising:
a slidably rotatable member having an inner surface and an opposite outer surface;
two insert support sidewalls and a base transverse thereto, a first of the two insert support sidewalls being fixed relative to the base and having two coplanar spaced apart insert location surfaces, a second of the two insert support sidewalls being slidably rotatable relative to a fixed inner wall of the cutting insert pocket and having two coplanar spaced apart insert location surfaces, the fixed inner wall being adjacent the outer surface of the slidably rotatable member, the two insert support sidewalls being angularly disposed to one another, the second insert support sidewall being the inner surface of the slidably rotatable member, the two insert support sidewalls being angularly disposed to one another at a first angular disposition;
(ii) providing a cutting insert to be retained in the cutting insert holder, the cutting insert having at least two angularly disposed insert peripheral side surfaces being disposed at a second angular disposition;
(iii) positioning the cutting insert in the cutting insert pocket with the two coplanar spaced apart insert location surfaces of the first insert support sidewall adjacent one insert peripheral side surface and the two coplanar spaced apart insert location surfaces of the second insert support sidewall adjacent the other insert peripheral side surface;
(iv) inserting a clamping screw in a through bore in the cutting insert until the clamping screw mates with a threaded bore in the base of the cutting insert pocket;
(v) screwing the clamping screw into the threaded bore in the base of the cutting insert pocket, whereby the slidably rotatable member becomes fixed in position between the cutting insert and the fixed inner wall adjacent the outer surface of the slidably rotatable member and the two coplanar spaced apart insert location surfaces of the first insert support sidewall abut one insert peripheral side surface and the two coplanar spaced apart insert location surfaces of the second insert support sidewall abut the other insert peripheral side surface.